Greenert accepted the Navy’s highest military post from Adm. Gary Roughead, who will retire Sept. 30 from the post he has held since September 2007. Both officers are Naval Academy graduates; Roughead, in 1973, and Greenert, in 1975.

Greenert, who previously served as vice chief of naval operations, will now become a member of the Joint Chiefs of Staff. In that capacity, he will serve as principal naval adviser to Navy Secretary Ray Mabus and President Barack Obama.

Mabus said the Navy will go through a transparent transition with Greenert now serving as its top officer.

“Admiral Roughead's contributions may be hard if not impossible to surpass, but I am confident that if anyone can match them it is Jon Greenert,” Mabus said.

Greenert praised Roughead’s example and said he would strive to follow it.

"My priorities, our course, are one, we've got to remain ready to meet the current challenges today, we've got to build a relevant and capable future fleet, and we have got to continue to care for our sailors, our civilians and their families, and recruit and nurture a motivated, relevant and diverse force," he said.

Greenert said he will focus on three tenets while in office: warfighting first, operate forward and be ready.

"We will approach our challenges and we will implement our changes that will have to be done in the future with three tenets in mind," he said. "They will be effective [and] efficient. Our solutions will be joint and the Marine Corps will remain our primary partner."

Mabus, who served as keynote speaker for the ceremony, highlighted Roughead's accomplishments during his naval career while thanking him for his leadership.

"I don't think anyone can ever fully express how much we're going to miss Gary Roughead's counsel and absolutely unwavering commitment to the Navy [and] the United States," said Mabus.

"Admiral Roughead has had the genius and the skill to turn so many of the challenges he's faced into opportunities," he said.

Mabus reviewed Roughead's career milestones, including being one of only two Navy admirals to command both the Pacific and Atlantic fleets.

"As chief of naval operations, his leadership has helped to reshape the Navy into the 21st century, operationally and strategically," said Mabus. "Gary Roughead's leadership skills follow great officers and a willingness to innovate while respecting the deep traditions of the sea service."

Mabus spoke about Roughead's commitment to his sailors, and how he always made them his first priority. "He never lost sight of the primary responsibility of leadership -- taking care of the people entrusted to you and to the office you hold," he said.

As Roughead took the podium, he thanked his counterparts, both foreign and domestic, friends and his family for their continued support and guidance during his tenure. He spoke about his unique experiences in the armed service, especially in the relationships built.

"There has been a lot of change, but throughout, there has been the decisive, constant and the aspect of the Navy that will be my enduring memory - our sailors," he said.

In an emotional conclusion, Roughead summarized his naval career.

"To echo what another Navy man said nearly five decades ago at this academy, when asked what I did to make my life worthwhile, I will respond with a great deal of pride and satisfaction, ‘I served in the United States Navy,’” he said.